Mineralogical study of archaeological copper slags found in the area of the Boyadzhik village, Yambol region, Southeast Bulgaria
Author: 02.12.2020, Published:
Tzankova, N., D. Stavrakeva. 2020. Mineralogical study of archaeological copper slags found in the area of the Boyadzhik village, Yambol region, Southeast Bulgaria. -Journal of Mining and Geological Sciences, Volume 63, 2020, 267-271.
ABSTRACT. In this paper, we present the results from a phase-chemical and structural study of metallurgical slags, found in an archaeological site near the village of Boyadzhik, Yambol region. The studied samples are mainly composed of SiO2 (37.22 – 37.45 %), Fe2O3 (36.26 – 36.71 %), CaO (11.11 – 11.66 %) and Al2O3 (6.03 – 6.15 %). The dominant phase is fayalite, followed by magnetite and maghemite, augite, and augite-type pyroxene closest to esseneite. These minerals were observed microscopically in transmitted and reflected light and were established by XRD study and SEM CDD-EDS microanalyses. The copper in the studied slags goes up to 2.46 % indicating low process efficiency of copper extraction from the raw material. The copper was presented by metallic droplets as well as copper-oxide and copper-iron-oxide phases. No relics of sulfide minerals and sulfur-containing phases were found in the analyzed samples. The mineral composition of the studied samples and their structural and phase peculiarities allow us to define these materials as by-products (slags) from copper-containing oxidic ore smelting.
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